1. Field of the Invention
The present invention relates to an art which displays maps for a plurality of routes from a departure point to a destination.
2. Description of Related Art
There is a known method for simplifying the shape of a road based upon map data for displaying a map. For example, with the apparatus disclosed in Japanese Patent laid-open application Publication No. 11-202762, the shape of the road is simplified by performing procedures such as straightening and orthogonalization and the like upon the links which specify the road shape in the map data, and by displaying only landmark information within a range which is regulated by a mask. A map which is easily viewed is provided by displaying a map using the road shapes which have been simplified in this manner.
However, when displaying road shapes of a plurality of routes simultaneously while simplifyng each of them with the apparatus disclosed in Japanese Patent laid-open application Publication No. 11-202762, if these routes overlap one another, then these overlapped portions may be difficult to see. Due to this, an apparatus is required which can perform display for routes in an abridged map of which the road shapes have been simplified so that a plurality thereof mutually overlap one another, so that it is possible to distinguish between the various routes in such an overlapped portion.